Separation of Ni and Co from lithium-ion batteries through chloride coordination and electrodialysis

The sustainable recovery of valuable metals from spent lithium-ion batteries (LIBs) is crucial for a circular and environmentally friendly economy as the LIBs market expands. However, separating and recovering Ni 2+ and Co 2+ is challenging due to their similar physicochemical properties. This study presents a new approach to enhance Ni/Co separation by manipulating chloride coordination to impart opposite charges to the metal ions. By adjusting the Cl − concentration, Ni 2+ and Co 2+ are selectively complexed into [Ni(H 2 O) 5 Cl] + and [CoCl 4 ] 2− clusters, respectively. Coupling this coordination strategy with electrodialysis, we achieved a remarkable Ni 2+ /Co 2+ separation selectivity of up to 370.70. When applied to NCM or NCA battery leachate solutions, the separation selectivity remained high, reaching 90.60 and 109.42, respectively, despite variations in metal ion concentration ratios. This chloride coordination-assisted electrodialysis strategy offers a promising alternative for Ni/Co separation, a critical step in the hydrometallurgical recycling of LIBs